1. Field of the Invention
The invention is directed to an ink metering system in a printing press that is divided into ink zones, whereby each of which has a piezoelectrical actuating drive.
Piezoelectrical actuating drives are known per se, as can be seen from Published, Non-Prosecuted German Patent Application No. 44 45 642 A1, and are used in different technical fields.
German Utility Model No. 91 12 926 U1 describes an ink metering system corresponding to the ink metering system of the aforementioned species. The regulation, actually the control, occurs according to a stored characteristic curve reproducing the context by an applied voltage and alternation of length of the piezoelectrical actuating drive, so that the status message of the respective position of the metering element via potentiometer, as known from other ink metering systems, is not necessary with respect to the ink metering system described in the aforementioned utility model.
What is disadvantageous about it is that hydrodynamic influences of the metered printing ink on the ink metering system and a drift of the metering element occurring in the actuating drive as a result of typesetting processes remain unconsidered.
It is accordingly an object of the invention to provide an ink metering system in a printing press that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which operates in a more metering-stable manner.
With the foregoing and other objects in view there is provided, in accordance with the invention, an ink metering system for a printing press having a roller divided into ink zones. The ink metering system includes a control device for each of the ink zones. The control device has a piezoelectrical actuating drive and a sensor.
A critical advantage of the inventive ink metering system is its high metering stability.
Modifications of the distance of the metering element from a roller occurring during the metering operation are measured by the sensor and are compensated via a status message by the control device, so that the distance is kept the same under all operating conditions. The metering system is allocated to the roller.
In accordance with an added feature of the invention, the control device has a metering element and the piezoelectrical actuating drive engages the metering element for adjusting the metering element and a distance between the metering element and the roller is a measuring variable of the control device.
In accordance with an additional feature of the invention, the sensor is a distance sensor secured to the metering element and is directed toward the roller.
In accordance with another feature of the invention, the control device has a metering element and the piezoelectrical actuating drive engages the metering element for adjusting the metering element. The control device has a machine element disposed adjacent the metering element, and a distance between the metering element and the machine element is the measuring variable of the control device.
In accordance with a further feature of the invention, the sensor is a distance sensor fastened to the machine element and is directed toward the metering element.
In accordance with a further added feature of the invention, the control device has a gear with a gear element, the piezoelectrical actuating drive and the metering element are connected in terms of driving through the gear element.
In accordance with a further additional feature of the invention, the gear is a translation gear for translating a short regulating distance of the piezoelectrical actuating drive into a long regulating distance of the metering element.
In accordance with another further feature of the invention, the sensor is a deformation sensor attached to the gear.
In accordance with an added feature of the invention, the gear has a flexible joint.
In accordance with a further feature of the invention, the piezoelectrical actuating drive and the metering element have regulating directions deviating from one another.
With the foregoing and other objects in view there is provided, in accordance with the invention a printing press containing a roller divided into ink zones and an ink metering system having a control device for each of the ink zones. The control drive has a piezoelectrical actuating drive and a sensor.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an ink metering system in a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.